Bicycle enthusiasts have been motivated to use the upstroke of their legs for motive power and to be able to pedal at a fast rate. Over the years pedals have been equipped with metal or plastic clips to receive the toe of the shoe and strape to tightly hold the shoe.
Additional force could be exerted by using shoes that have a cleat that fits into the pedal with the strape tightened subsequently. This combination has very good efficiency, and the bicycle can be ridden with cleated cycling shoes, or less efficiently with normal walking shoes; but when the bicycle is ridden with cleated cycling shoes strapped into the pedals under toe clips, there is no way for the cyclist to remove his feet from the pedals without reaching down by hand and unbuckling the strape. This operation takes some time and can not be done while pedaling or with both hands on the controls of the machine and is considered dangerous in an emergency thus the cyclist is forced to choose between maximum efficiency and reasonable safety.
Recently there has been the development of clipless, quick release pedals that retain the shoe on the bicycle pedal by attaching to the cleat when the shoe is in its normal position, but allowing the cyclist to escape the pedal by moving the foot in some none pedaling direction. These pedals are considered an advance in safety, but typically do not allow conventional shoes to be worn at all when operating the bicycle, and the cleats are considerabely bigger than the cleats used formerly, so there is less load per square area, and the cleats are more slippery. Additionally, the cleats are a precision component that are sensitive to wear from contact with pavement and to clogging by earth or other matter. The location of the cleats on the shoe is very critical, often requiring skilled fitting using special equipment. Walking wears out the cleats requiring both the replacement of the cleat and the utilization of custom fitting.
The effect of these developments is to cause serious cyclists using clipless pedals to dedicate their riding to a portion of their life less integrated with other activities, and to carry other shoes if they contemplate having to walk because of mechanical failure or to enjoy any activity on foot.
Heretofore shoe covers have been developed to provide a walking surface for cleated cycling shoes by two basic methods. The first method consists of a cover which surrounds the toe of the shoe and the heel of the shoe and usually has a strap that is crossed over the top of the foot after the shoe is installed in the cover as in U.S. Pat. No. 4,055,005 to Meinhart, 1977. This cover is by its nature required to be approximately as large as the cycling shoe itself, require several different materials in its manufacture, hide the aesthetic design of the cycling shoe, and require relatively greater amounts of material and thus weigh more than other designs. Because it must cover the entire length of the cycling shoe it is necessarily larger and more difficult to store on the cyclist's person or bicycle and requires a greater range of sizes to fit on every size shoe.
The second method involves attaching permanently onto the shoe attaching devices for adding a walking sole, as in U.S. Pat. No. 4,807,372 to McCall, 1989 requiring the cyclist to alter his shoes and thus change the appearance of the shoe. This approach also increases the rotating weight when pedaling, which serious cyclists are always trying to reduce by developing lighter pedals, shoes, and crank components. There is on the market a product named Kool Kovers.TM. which encases the cleat only and provides as its object protection of the cleat from wear, it worsens the elevation of the sole of the shoe, provides no heel elevation, and has very little surface area for attachment and thus is subject to coming off in use.